This is a Shannon Award providing partial support for research projects that fall short of the assigned institute's funding range but are in the margin of excellence. The Shannon award is intended to provide support to test the feasibility of the approach; develop further tests and refine research techniques; perform secondary analysis of available data sets; or conduct discrete projects that can demonstrate the PI's research capabilities or lend additional weight to an already meritorious application. The abstract below is taken from the original document submitted by the principal investigator. We have cloned two novel genes (termed 1E4 and 1C11-5) that are expressed preferentially by cells of dendritic cell lineage, including Langerhans cells (LC), and that encode new members of the C-type lectin family. We hypothesize that 1E4 and 1C11-5 polypeptides are expressed on LC and they mediate efficient uptake of glycosylated antigens. Our specific aims are: 1) To determine the cellular and subcellular locations of these 1E4 and 1C11-5 polypeptides. We will produce anti-1E4 and anti-1E4 and anti- 1C11-5 antibodies (to study tissue- and cellular-distributions) and stable transfectants that express 1E4 and/or 1C11-5 cDNAs (to study subcellular localizations). 2) To identify the function of the 1E4 and 3C11-5 polypeptides. Chimeric proteins consisting of GST and the extracellular domains of 1E4 or 1C11-5 will be examined for their binding of glycosylated BSA probes, and 1E4 and/or 1C11-5 transfectants will be examined for endocytosis of these probes. 3) To study the functional roles of 1E4 and 1C11-5 in the presentation of glycosylated antigens by LC. We found that freshly procured LC present glycosylated antigens to T cells more efficiently than non-glycosylated antigens. The relative contributions of 1E4 and 1C11-5 polypeptides to this function will be determined using antibodies, GST fusion proteins, and monosaccharide competitors. We will also determine whether the same inhibitors block delayed-type hypersensitivity reactions to glycosylated antigens in mice. 3) To characterize domain structures of the 1E4 and 1C11-5 polypeptides. Deletion/substitution mutants of 1E4 and 1C11-5 will be tested for their relative capacities to bind (cell-free system) and internalize (transfection system) glycosylated BSA probes. 4) To study the structure and functions of truncated forms of 1E4 and 1C11-5 mRNAs. We will clone cDNAs for these truncated mRNAs to study the structures and functions of their products. Insight gained will clarify mechanisms in antigen uptake by LC and may lead to new strategies for treating T cell-mediated inflammatory skin disorders by regulating 1E4/1C11-5-mediated endocytosis of glycosylated antigens by LC.